circle.java

可以让初学者有一个感性的认识

import java.io.*;
public class Circle
{
	int radius;
	
	public Circle(){radius=1;}

	public int getRadius(){return radius;}

	public void setRadius(int newRadius){radius=newRadius;}

	public double circleArea()
	{
		return Math.PI*radius*radius;
	}

	public double circleLength()
	{	
		return 2.0*Math.PI*radius;
	}
}